Patient specific robotic bone implant positioning

Abstract

A robotic system is provided for assisting during bone surgery, adapted to control the position of a limb. The robotic system includes a robotic arm connected to a fixation device for rigidly connecting the distal bone to the robotic arm and allowing movement in six degrees of freedom. Specifically, the fixation device provides at least two fixation points to the distal bone. The first fixation point can be rigidly connected to the distal bone near the joint and the second fixation point can be rigidly connected to a distal position of the distal bone. The rigid connection of the distal bone to the robotic arm allows the robotic system to impose controlled movement on the distal bone in six degrees of freedom.

The invention claimed is: 
     
       1. A robotic system for assisting during bone surgery, the robotic system adapted to control a position of a limb including a distal bone, the robotic system including a robotic arm and a fixation device connectable to the robotic arm,
 the fixation device adapted for rigidly connecting the distal bone to the robotic arm, 
 the fixation device comprising at least two fixation elements, 
 wherein a first fixation element of the at least two fixation elements is provided at a first end of the fixation device and connectable to a proximal region of the distal bone for fixating the robotic arm with the distal bone allowing the robotic arm to impose movement on the distal bone in a first set of degrees of freedom and a second fixation element of the at least two fixation elements is provided at a second end of the fixation device opposite the first end and connectable to a distal region of the distal bone for fixating or rigidly connecting the distal bone to the robotic arm to impose movement on the distal bone in a second set of degrees of freedom, 
 wherein a connection between the robotic arm and the fixation device is positioned between the first fixation element and the second fixation element, 
 the robotic arm thus adapted for imposing movement in  6  degrees of freedom to the distal bone, 
 wherein a distance between the first fixation element and the second fixation element is at least 30% of a length of the distal bone. 
 
     
     
       2. The robotic system of  claim 1 , the fixation device adapted for fixating the distal bone in the 6 degrees of freedom. 
     
     
       3. The robotic system of  claim 1 , the at least two fixation elements adapted for fixating the distal bone in the 6 degrees of freedom, the first fixation element adapted for fixating the distal bone in a first set of the 6 degrees of freedom and the second fixation element adapted for fixating the distal bone in a second set of the 6 degrees of freedom. 
     
     
       4. The robotic system of  claim 1 , the robotic system being adapted for simultaneously imposing an identical movement to both the first and second fixation element. 
     
     
       5. The robotic system of  claim 1 , the robotic arm being rigidly connectable or rigidly connected to both the first and the second fixation element. 
     
     
       6. The robotic system of  claim 1 , the first fixation element and the second fixation element being rigidly connectable or rigidly connected to each other. 
     
     
       7. The robotic system of  claim 1 , wherein the first fixation element is connectable to the proximal region of the distal bone for fixating the robotic arm with the distal bone allowing the robotic arm to impose movement on the distal bone in three orthogonal directions of translation and at least one axial rotation around a longitudinal axis of the distal bone in a plane perpendicular to said longitudinal axis. 
     
     
       8. The robotic system of  claim 1 , wherein the second fixation element is connectable to the distal region of the distal bone for fixating or rigidly connecting the distal bone to the robotic arm allowing the robotic arm to impose movement on the distal bone in at least a rotational degree of freedom being flexion-extension rotation and/or vargus-valgus rotation. 
     
     
       9. The robotic system of  claim 1  adapted to control a position of a proximal bone of the limb, the system comprising a further robotic arm or an external mechanism and a fixation device connectable to the further robotic arm or the external mechanism, including at least one further fixation element connectable to a distal region of the proximal bone for fixating the further robotic arm or the external mechanism with the proximal bone of the limb allowing the further robotic arm or the external mechanism to impose movement on the proximal bone of the limb in at least one degree of rotational freedom. 
     
     
       10. The robotic system of  claim 1  wherein the first fixation element includes at least two pins for attaching to the distal bone in direct physical contact thereto. 
     
     
       11. The robotic system of  claim 1  further including a processing unit for controlling or fixing a position of at least the distal bone, the robotic system further including a sensing system for measuring the position of at least the distal bone as part of said controlling and fixing. 
     
     
       12. The robotic system of  claim 1  further comprising beacons rigidly fixed to at least the distal bone fixation device for motion tracking of at least the distal bone fixation device. 
     
     
       13. The robotic system of  claim 1 , the limb comprising a joint and corresponding ligaments, the robotic system further being adapted to perform ligament testing, the robotic arm adapted to provide motion to a distal bone with respect to a proximal bone of the limb, the robotic arm further including a sensor to measure a response of ligaments of a joint between the distal bone and the proximal bone, for assisting in implant alignment and/or soft tissue releases. 
     
     
       14. The robotic system of  claim 1  further including means for measuring mass properties of a distal part of the limb. 
     
     
       15. The robotic system of  claim 14 , the system being further adapted to provide motion and simultaneous force measurement with the means for measuring mass properties of the distal part of the limb, to determine a mass and center of mass of the distal bone in order to compensate for an effect of changed distal bone orientation on the force measurement, thus, to avoid influence of an orientation of the distal bone on derived internal knee force measurements. 
     
     
       16. The robotic system of  claim 1  further adapted to stabilize the limb for positioning an implant and/or cutting the bone. 
     
     
       17. The robotic system of  claim 1  further including a second robotic arm adapted to receive a cutting tool for cutting portions of the bone. 
     
     
       18. The robotic system of  claim 1  wherein the robotic arm is programmed to, after implants are installed, measure post-operative laxity. 
     
     
       19. The robotic system of  claim 1  wherein the first fixation element is connectable to the proximal region of the distal bone by directly attaching to the distal bone, and
 wherein the second fixation element is connectable to the distal region of the distal bone by non-invasively attaching to the distal bone.